Understanding the GitHub Actions Environment

Here's all that you need to know on how to handle:

• Environment Variables
• Outputs
• States

Environment Variables

Use these when you're going to use them all across a GitHub Actions file.

For instance this could be the name of a host you want to connect to or a secret token.

There are 3 ways to set environment variables:

1. In GitHub if you're going to use them across different files

1. Go to your repository
2. Go to settings
3. In the left panel select "Secrets and variables"
4. Click on "Actions"
5. Store any variables and secrets you want to use in your actions files.
6. In the file you can get these by USING $NAME_OF_YOUR_VARIABLE_OR_SECRET

2. In the env section of an Action .yml file

Useful when you're going to use it across a whole file. This saves time if the value will ever change, only needing to change one line instead of multiple ones.

env:
  COLOR: yellow

...

steps:
  - name: Print my color
    run: printf '%s\n' "$COLOR" # This will output 'yellow'

3. In a step in the Action .yml file

This is useful if the variable is going to be used across an Action but the variable is set dynamically in a step.

steps:
  - name: Set the value
    id: step-one
    run: |
      echo "COLOR=yellow" >> $GITHUB_ENV

  - name: Use the value
    id: step-two
    run: |
      printf '%s\n' "$COLOR" # This will output 'yellow'

Outputs

Outputs are useful when you want to get data from specific steps.

- name: Set color
  id: set-color
  run: echo "SELECTED_COLOR=green" >> $GITHUB_OUTPUT

- name: Get color
  env: SELECTED_COLOR: ${{ steps.color-selector.outputs.SELECTED_COLOR }}
  run: echo "The selected color is $SELECTED_COLOR"

States

States are a bit different in that they are state variables that can be shared between execution files.

If you're using pre:, main: and post: workflows in actions you can set a state to be shared in those files:

runs:
  using: 'node20'
  pre: 'setup.js'
  post: 'cleanup.js'

...

- name: Save state
  run: echo "{name}={value}" >> $GITHUB_STATE

In the .js files you can get the state by:

process.env.STATE_variableName